Green glowing craft which changed shape and color when it landed on the highway.

My boyfriend and I were driving north on route 3 out of Colebrook towards Pittsburg, on Mon. July 3 at approx. 10:30 p.m. on a cloudy and drizzly night. We were talking and we both both took notice of all the fire flies in front of our jeep. Then looking out of the windshield I say a capsule shaped green glowing object in the sky directly over head and said to my boyfriend, what the hell is that a giant fire fly, he looked and then in the next instant it landed infront of us on the highway the only way we were able to see this was because of the huge flash of green light that it gave off. I immedaitley turn the car around and drove the opposite direction. While I was doing this my boyfriend saw the craft it was disk shaped, black with red under glow. We were driving away, not being able to move very fast because of the weather conditions, we travled at least four miles when I spotted the craft now glowing solid green following us it was about a mile away just above tree line, I told my boyfriend that it was behind us and he saw the same thing too. So I sped up driving at least 75 miles per hour. We were both terrified and did not get a good or curious feeling from or about this thing. When I looked again in the rearview it was not there. We drove what seemed like an enternity back into Colebrookand reported it to the police.